The Unicorn's Secret Series by Kathleen Duey

Heart Trilby has no family. She lives a hard and lonely life in the dusty village of Ash Grove -- until she finds a scarred, skinny mare in the forest. Against the wishes of her guardian, mean-spirited Simon Pratt, Heart adopts the mare and names her Avamir. Heart is thrilled when she realizes Avamir is in foal. But when the colt is born weak and disfigured, Simon decides to sell Heart's beloved horses to be slaughtered by the town's soapmaker... moreHeart Trilby has no family. She lives a hard and lonely life in the dusty village of Ash Grove -- until she finds a scarred, skinny mare in the forest. Against the wishes of her guardian, mean-spirited Simon Pratt, Heart adopts the mare and names her Avamir. Heart is thrilled when she realizes Avamir is in foal. But when the colt is born weak and disfigured, Simon decides to sell Heart's beloved horses to be slaughtered by the town's soapmaker. Can Heart find a way to protect them -- and the only love she has ever known? less

When her beloved Moonsilver, the unicorn, is nearly killed by a hunter's arrow, Heart sneaks back into her village to get help froth the healer, Ruth Oakes. But even greater danger awaits Heart and Moonsilver in Ash Grove. Rumors of Moonsilver's secret have reached the ears of the cruel Lord Dunraven. Once again Heart must flee, with Ruth's mysterious gift -- a silver thread -- to protect her and Moonsilver.

Heart must hide her beloved unicorn, Moonsilver, from Lord Dunraven's hunters. She and her animal friends join a troupe of traveling minstrels. Everyone thinks Moonsilver's horn is fake -- just part of the act. Then Moonsilver heals a badly injured boy right in front of the audience, and the unicorn's secret is in danger. Can Heart's mysterious silver bracelet, which makes her dream of the magical Mountains of the Moon, help her find the one place Moonsilver might be safe?

Heart has to find a safe haven for her beloved unicorns. With Lord Dunraven looking for them -- and Heart's friends aware that helping her will bring Dunraven's anger -- she has nowhere to turn. If only she knew where her family was -- or who they were. In a mysterious bundle of paper in Dunraven's castle Heart finds a drawing that looks like the design on her baby blanket. The paper is covered with tiny symbols... moreHeart has to find a safe haven for her beloved unicorns. With Lord Dunraven looking for them -- and Heart's friends aware that helping her will bring Dunraven's anger -- she has nowhere to turn. If only she knew where her family was -- or who they were. In a mysterious bundle of paper in Dunraven's castle Heart finds a drawing that looks like the design on her baby blanket. The paper is covered with tiny symbols. If she can find out what they mean will they unlock the secrets of the dreams that have been haunting her? less

Heart must find her family and a safe haven for the unicorns. A drawing in the book from Dunraven's castle shows the same unicorn design as her foundling blanket! Perhaps the book tells more about her family -- but she cannot read it. Searching for a teacher, she finds a blacksmith whose family forge was made by unicorn magic. His old records show that his grandfather made giant iron gates using the same design... moreHeart must find her family and a safe haven for the unicorns. A drawing in the book from Dunraven's castle shows the same unicorn design as her foundling blanket! Perhaps the book tells more about her family -- but she cannot read it. Searching for a teacher, she finds a blacksmith whose family forge was made by unicorn magic. His old records show that his grandfather made giant iron gates using the same design. If Heart can find those gates perhaps she will find her family -- but will Dunraven's men find her first? less

In the beautiful armor Joseph Lequire has created for Moonsilver, no one can tell he is a unicorn. It's safe for Heart to travel to Bidenfast, where she hopes to find her Gypsy friends. But the streets are jammed with people in town for the crowning of the new Lord Irmaedith, and the young lord himself takes a special interest in the unicorns. Will Heart be able to keep her secret?

It has been a long, hard winter, and the Gypsies are glad to be leaving Lord Levin's mountains for the sunny plains of Lord Kaybale's lands. But that means time is running out for Heart. The old stories say that Castle Avamir is higher than the clouds, deep in a valley, under the stars, and over the moon. It makes no sense -- but if Heart can't solve the riddle, she might never find a safe haven for her beloved unicorns.

Heart is convinced that the old man from Castle Avamir can help her find her family -- the only people she dares to trust with the Unicorn's secret. But the old man has been taken prisoner by Lord Dunraven. Heart's search for the truth is leading her into the most dangerous place of all: the depths of Dunraven's heavily guarded castle. Heart's quest is nearing its end -- and what awaits her is beyond her wildest imaginings....